I have this idea for a fic, but I don't think I could do it justice, so I figured I'd see if other people wanted to take a crack at it.

There's this song, by a pretty obscure band, that reminded me of the various villains of the show. It's called Crown of Roses, by The Knitted Cap Club (it's a pretty obscure band; I only know about them because my high school choir director's the lead singer).
The chorus, especially, is what gave me the idea:
"Ambition was their greatest downfall, accompanied with lies. It brought about their destruction and pitiful demise. All for the want of power, the symbol of the crown. In greed and thirst for greatness, all the roses drowned."

For the most part, it fits Moriarty, but I can see it working for Irene Adler and Eurus as well, along with the rest of the villains in some ways.